Around that time, an ambulance left the cave area and headed toward a helicopter, which landed at a nearby hospital.

The eight Thai boys rescued from the caves over the weekend and Monday were quickly taken to the hospital and put in isolation rooms as medical teams evaluate the strain on their bodies from nearly two weeks underground.

"The eighth person is out and the operation is done for today", Sitthichai Klangpattana, flag officer to Thailand'sNavy SEAL commander, told AP. Another five still await rescue, including the team's 25-year-old coach.

An Australian doctor who is part of Sunday's rescue mission checked the health of the boys on Saturday night and gave the all-clear for the rescue to proceed.

Authorities have not confirmed the identity of the rescued boys and some of the parents said they had not even been told who had been rescued.

The second phase of a rescue operation has ended for the day, with more than half of the Thai soccer team rescued from the cave.

For the final operation tomorrow, Mr Narongsak said the rescuers would use the same plan with some adjustments because the number of survivors to be extracted would be five instead of four as was the case for the last two days.

"If we wait and the rain comes in the next few days we will be exhausted again from pumping and our readiness would drop".

Eight more boys and their coach need to be removed from the cave, and the rescue has resumed, CNN reports.

Authorities had said that incoming monsoon rains that could send water levels in the cave rising, coupled with falling oxygen levels in the enclosed space, added to the urgency of getting those trapped out. Some stretches of the Tham Luang cave are more than 10m (33ft) high, while others are a tight squeeze through water-filled passages.

Still, the four were undergoing medical checks in a hospital in the provincial capital and were not yet allowed close contact with relatives due to fear of infections.

A crack team of foreign divers and Thai Navy SEALS guided four boys on Sunday and a further four on Monday through narrow, submerged channels from the muddy bank deep inside the Tham Luang cave where they had been stranded for more than two weeks.

Those four boys were hungry but in good spirits, officials said on Monday.

Rescued schoolboys are moved from a military helicopter to an awaiting ambulance at a military airport in Chiang Rai, Thailand, July 9, 2018.

A device by Elon Musk'sSpaceX and The Boring Company, created to help rescue the remaining members of a soccer team trapped in a flooded cave in Chiang Rai, Thailand, is being tested in a swimming pool in Los Angeles, California, in this still image taken from an undated video obtained from social media.

Two divers will accompany each of the boys, all of whom have been learning to dive only since July 2, when the first searchers found them.

Typically people would learn to scuba dive before embarking on a more technically challenging cave dive like the one involved in the rescue effort, said Chris Foisey, a St. Catharines, Ont. -based scuba instructor with experience diving through underwater tunnels. Last week, Musk sent engineers from two of his companies, SpaceX and Boring Co., to assist Thai officials in the rescue effort, which comprises a large team of worldwide diving, engineering and medical experts, among other professionals.